Field of the Invention
The invention relates to a door check for vehicle doors, e.g. car doors. The door check comprises a door strap for being mounted to the chassis or the door. The door strap is received by a retainer for being mounted to the door or the chassis, respectively. The door strap is movably supported by the retainer enabling a movement of the door strap relative to the retainer at least in the longitudinal direction of the door strap. The retainer comprises a cylinder with a piston, the latter being pressed against the door strap to provide friction slowing down a movement of the door strap relative to the retainer.
Description of the Background Art
When opening a car door, the movement of the door has to be stopped at last when the maximum opening angle of the door hinges is reached. In most cases the space to the left or right of the car, respectively is not sufficient to fully open the door. The door is likely to be slammed against neighbored cars, garage walls or the like. To avoid damages, car doors are equipped with door checks. The door checks mostly provide multiple defined opening angles. A person opening the door opens the door in increments until he or she expects the door to hit an obstacle if the opening angle is further increased.
EP 1 951 977 B1 discloses an example for a vehicle door check. The door check comprises a retainer with an essentially U-shaped linear bearing supporting a door strap. The door strap is pressed by a spring loaded piston into the U-shaped linear bearing to thereby provide friction slowing the swinging door down. The door strap is an essentially elongate slider with increasing thickness towards its mechanical end stop to thereby adapt the friction. However, this door check shows a significant slip stick effect due to the initial breakaway torque.
There have been attempts to reduce the slip stick effect, e.g. by using viscous type dampers with magnetorheological fluids. Another approach is provided by DE 10 2013 014 845 A1, whereby the door strap is clamped between an abutment and a brake shoe (or two brake shoes) with a lining. The brake shoe is spring loaded by a disk spring against the door strap. To reduce the slip stick effect a linear actuator lifts off the brake shoe and thus the lining to at least reduce the friction between the lining and the door strap and thus the initial breakaway torque.
Other means for braking a door strap are disclosed e.g. in DE 103 20 138 B4, which corresponds to U.S. Pat. No. 7,363,785, and WO 2008/100233 A2